Many products today utilize films. Some examples of such products include, but are not limited to, personal care absorbent products such as diapers, training pants, incontinence garments, sanitary napkins, bandages, wipes and the like, as well as products such as packaging materials, and other disposable products such as trash bags and food bags. These films are typically made from thermoplastic polymers.
Many thermoplastic polymers are derived from monomers that are obtained from non-renewable, fossil-based resources such as petroleum, natural gas, and coal. In recent years, as manufacturers and consumers have gained a greater awareness of environmental and sustainability concerns, the demand for polymers made from renewable, non-fossil-based materials has grown significantly. Unfortunately, however, many renewable thermoplastic biopolymers are not well suited for solo use in stand-alone applications. Associated with the desire to reduce utilization of non-renewable natural resources, the ability to “down-gauge” or reduce the thickness and/or polymer content of films, products and packages while maintaining performance is also advantageous. Technologies that reduce the utilization of non-renewable natural resources through incorporation of biopolymers while also enabling down gauging are highly desired.
Attempts have been made in the art at producing films, fibers and other compositions from renewable biopolymers, such as polylactic acid (see, e.g., EP 2285892; WO 2008/149943; U.S. Pat. Nos. 5,910,545; 6,177,193; 6,309,988; 6,506,873; 7,132,490; 8,137,773; 8,461,262; 2009/0263600; 2009/0326152; 2009/0324911; 2012/0035323; 2012/0219783; 2013/0157032 and 2013/0190408). However, the use of PLA may result in deficiencies in the context of making thin, flexible packaging films such as those typically used for personal hygiene articles, wipes, product bags, and for personal care products. For instance, PLA thin film exhibits high stiffness, brittleness, high rustling noise levels when handled, low extensibility, low ductility, and low toughness relative to polyolefin. As such, PLA is not typically used as a major component in films for such applications.
Thermoplastic polymers such as polyolefins (“PO”) are commonly used to produce thin films for consumer product packaging because of their excellent proccessability. As a result, common film-manufacturing equipment is optimally designed for making polyolefin-based films. Replacing or modifying this manufacturing equipment to run other types of polymers would require high development costs and excessive capital expenditures, making this option impractical for most manufacturers.
Accordingly, thermoplastic polymer compositions that are not only suitable for making thin films using standard polyolefin film-manufacturing equipment, but also contain bio-based content having good mechanical properties, are highly desirable.